Apparatus and process for steam processing of textile articles



E. S. GORDON July 11, 1967 APPARATUS AND PROCESS FOR STEAM PROCESSING OF TEXTILE ARTICLES Filed Dec. 30, 1964 INVENTOR 52% [or/ J Gordon mm, W.

United States Patent ice 3,330,451 APPARATUS AND PROCESS FOR STEAM PROCESSING OF TEXTILE ARTICLES Earl S. Gordon, Wilmington, Del., assignor to E. I. du

Pont de Nemours and Company, Wilmington, Del., a

corporation of Delaware Filed Dec. 30, 1964, Ser. No. 422,320 13 Claims. (Cl. 223-51) This invention relates to textiles and, more particularly, to steam processing textile articles.

Textile articles are treated with steam in order to accomplish a variety of results such as setting, shrinking, and surface-finishing. The steam treatment is usually carried out either in steam-filled pressure vessels containing the textile article, or on forms around which the textile article is placed. In the latter, wet steam and air are released within the form to pass through the fabric of the textile article and then to escape into the atmosphere. Such prior art practices are taught in US. Patents 2,848,146; 2,966,287; 2,849,167; and 2,443,557. There are, however, certain problems attendant with the former process. Textile articles such as stockings that have been steam processed in pressure vessels and then dyed, have been so lacking in color-uniformity that as many as 50% of the stockings have had to be rejected. This defect seems to be due in large part to the nature of the steam. When steam enters a large space which is at a lower pressure than the pressure of the entering steam, the pressure of the steam drops to the pressure of the space, but the enthalpy of the steam does not drop as quickly as does the steam pressure. Therefore, at first, the steam is locally superheated until equilibrium conditions of pressure and temperature are attained within the large space. Furthermore, because of eddy currents, the existence of both superheated and desuperheated steam persists in the pressure vessel. It is this absence of equilibrium conditions that apparently causes the lack of color uniformity. This is manifested in dyed stockings, for example, as streaks, spots, and other indications of uneven coloring.

It is therefore an object of this invention to provide means for equilibrating the steam used to treat textile articles.

It is another object to provide such means to be used in conjunction with known and available steam-treating devices and methods.

A further object of this invention is to provide efficient means for steam processing of hosiery whereby color non-uniformities in the dyed product are minimized.

Other objects will become apparent in the course of the fOlIOWing specification and claims.

These objects are accomplished in the present invention by the provision in an apparatus for steam-treating a textile article including a first vessel capable of confining steam at superatmosphen'c pressures and means for introducing steam into the first vessel, of a second vessel within the first vessel, the second vessel being constructed at least in part of a steam-permeable material capable of converting substantially all of the superheated steam into substantially saturated steam as the steam passes through the steam permeable material. The steam-permeable material, which is most preferably of a textile fabric construction, serves as a heat sink in order to convert the superheated steam to substantially saturated steam. At least the steam-permeable portion of the second vessel must be spaced from the inner surface of the first vessel, and in addition, means must be provided for supporting the textile article to be treated within the second vessel in spaced relation to the steam-permeable portion of the second vessel.

This invention, in all its various embodiments, will be 3,33a451 Patented July 11, 1967 more fully comprehended by reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of the first vessel containing the second vessel situated therein;

FIGURE 2 is a cross-section taken on line 2--2 of FIGURE 3 with a textile article suspended in the second vessel; and

FIGURE 3 is a cross-section taken on line 3--3 of FIGURE 2.

Referring to FIGURES 1, 2, and 3, the first vessel 1 (having steam inlet 3 and fluid outlet 8) completely encloses the second vessel 5. The first vessel 1 is equipped with suitable means such as a pressure-sealable door 4 through which the second vessel is introduced into the first. The second vessel 5, having a rigid frame 6, is sup ported within the first vessel 'by means of hangers 7 secured to the top of the first vessel and to rings 9 on the top of the second vessel 5. There is nothing critical about the support means employed. It is only necessary that the second vessel 5 be spaced from the inner surface of the first vessel 1. To support the textile article 13 Within the second vessel, a variety of conceivable means may be employed depending on, inter alia, the shape of the article to be treated. Hanger 11 secured to the lower face of the top of the second vessel 5 is suitable for this purpose. The hangers 11 must be of suitable design and placement to support the textile article 13 to be treated a suitable distance from the inner surface of the steam-permeable portions 15 of the second vessel 5. The textile article 13 to be treated can be introduced into the second vessel 5 through a door 14 which is closed during the steaming operation.

FIGURE 2 shows the minimum spacing of the steampermeable portion 15 of the second vessel 5 in relation to the nearest inner surface 17 of the first vessel, as well as the minimum spacing of the textile article 13 from the nearest inner surface 19 of the second vessel 5. For feed steam pressures up to about pounds per square inch gauge (9.49 kg. per square centimeter gauge) the distance a should be at least about 2 inches (5.08 centimeters) and the distance b should be at least about 1 inch (2.54 centimeters). For steam pressures greater than about 135 pounds per square inch gauge the distance a should be at least about 4 inches (10.16 centimeters) and the distance b should be at least about 3 inches (7.62 centimeters).

Although the first and second vessels. have been illustrated in the accompanying drawings to be cubical in shape, it is to be understood that the shapes of the vessels are not critical and that other geometric shapes may be suitable. The minimum spacing limitations noted above will remain unaltered for whatever vessel shape employed.

The second vessel which is to contain the textile article to be treated may be constructed wholly or in part of the steam-permeable material. Those portions of the second vessel not made of a steam-permeable material must be constructed of a steam-inert and steam-impermeable material which is preferably rigid such as aluminum. The aluminum or other steam-inert material employed serves as a form for the vessel so that its shape is retained. A particular suitable design is one in which the edges of the vessel are aluminum or are reinforced by aluminum.

The following example is given toillustrate the invention and is not intended to limit the scope thereof in any manner. In the example, parts, proportions, and percentages are by weight unless otherwise indicated.

Example Fifteen hundred dozen pairs of ladies nylon hosiery are knit with a"two-component side-by-side bright filanear comprising polyhexamethylene adipamide on one 'side 'and a 50/50 copolymer of .polyhexamethylene adipamide/polyhexamethylene sebacamide on the other side. The production of these filaments is taught in British Patent 950,429. The hosiery, in batches of 4 dozens each, are processed for 1 minute each batch in an interior vessel boarding oven vessel (such as delineated on attached FIGURES 1,2, and 3) with steam entering the 'oven at 353 F. (178.5 C.) and approximately 125 .pounds per square inch gauge (8.79 kg. per square centi-,

meter gauge). The temperature within the interior vessel is allowed to increase to the operating temperature of 245 F. (118.3 C.) and the pressure is then about pounds per square inch gauge (1.05 kg. per square centimeter gauge). The interior vessel is constructed of a cotton fabric having 68 endsper inch x 70 picks per inch (26.8 ends per cm. x 27.5 picks per'cm.) plain Weave, 2.9 ounces per square yard (98.2 grams per square meter). The interior vessel is given 'form and is supported by an aluminum frame with aluminum sheet, top and bottom. The hosiery are supported from the interior vessel top with hangers. As shown in FIGURE 2, the distance a is about 3 inches (7.62 centimeters), and the distance b is about 2 inches (5.08 centimeters). Directly'after steam treatment, the hosiery are dyed in a conventional stocking-dyeing machine, and then post-boarded.

Over 97% of the hosiery so processed in the apparatus of thisinvention and then dyed and post-boarded in a conventional manner show no streaks, spots, or indications of uneven coloring.

Identical control hosiery are processed in the same boarding oven with feed steam at 353 F. (178.5 C.) at approximately 125 pounds per square inch gauge (8.79 kg. per square centimeter gauge), but conventional other ly without any interior vessel.

Dyeing streaks and spots of a commercially unacceptable character are present in about 50% of the control hosiery. These non-uniformities areprincipally. on exposed edges of individual stocldngs as well as on the surfaces of the stockings located in the periphery of the batch being steam processed. However, some streaks and spots are also on stockings in the interior of the batch.

' the first-vessel wall and therefore will not be capable of acting substantially as a heatsink for the superheated steam. If the fabric is in contact with the article to be treated, the superheated steam would contact the article at the interstices of the fabric. But steam would enter the. interior vessel (to later become desuperheated steam) at areas that do not contact the article.'Therefore, an article in contact with the steam-permeable fabric would be,

processed by both superheated steam and desuperheated' steam, and dyeing non-uniformities will occur.

Although the apparatus of this invention finds utility inthe steam-treating of various textile articles, it is most suitable in the steam-processing of nylon hosiery, and particular nylon hosiery ,knit from the filaments described in Example I which are produced according to British Patent 950,429, the disclosure of which is intended to be incorporated herein by reference.

Many other equivalent modifications will be apparent to those skilled in the art and, therefore,.this invention is not'intended to be limited except as indicated in the appended claims.

What is claimed is: 1. In an apparatus for steam-treating a textile article including a first vessel capable of confining steam at su- The steam-permeable material employed in the apparatus of this invention acts as a heat sink for the temporarysuperheat of the entering steam, allowing only substantially saturated steam to reach the articles to be processed. In addition, the material diffuses the flow of steam to the'articles to be treated, and resists the passage of eddy currents. The steam-permeable material is preferably a textile fabric which has a sufiicient heat.-

' 35 picks per inch (13.8 picks per centimeter) and less than 35 ends per inch (13.8 ends percentimeter), permit the superheated steam to pass through the enclosure and then to contribute to dyeing non-uniformities in the stockings. Fabrics of too tight a weave greater than about 125 picks per inch and 100 ends per inch, impede too-greatly the flow of steam. The fabrics to be employed as the steam-permeable material inthe apparatus of this invention are preferably a woven textile of either natural or man-made fibers.

- As stated above, it is critical not to have the steampermeable fabric (whichforms at least a part of the textile-article-containing vessel) in contact with either the first-vessel wall or the article being processed. If the fabric is in contact with the first-vessel wall, the fabric will receive (by conduction) a large amount of heat from 35 ends per inch.

3. The apparatus ofclairn 1. wherein said steam-perperatmospheric pressures, and means for introducing steam into said first vessel, the improvement which comprises a second vessel within said first vessel, said second vessel being constructed at least in part of a steam-permeable material, at least that part of said second vessel being spaced from the inner surface of said first vessel, said steam-permeable material being a textile fabric capable of converting superheated steam intosubstantially saturated steam as the superheated steam permeates said steam-permeable material, and means for supporting said textile article within said second vessel in spaced relation ,to said steam-permeable material.

' 2. The apparatus ,of claim l'wherein said steam-permeable material is a textile fabric having a basis weight of at least about 1.5 ounces per square yard and a weave construction'of at least about 35 picks per inch and about meable material is a textile fabric having a basis weight of between about 1.5 ounces per square yard and about 4.9 ounces per square .yard and a weave construction of between about 35 and about 125 picks per inch and be tween about 35 and about 100 ends per inch. 7 V 4. In an apparatus for steam-treating a textile article including a first vessel capable of confining steam atv superatmospheric pressures, and means for introducing steam under a pressure of up to about 135 lbs./in. into said first vessel, the improvement which comprises a second vessel within said first vessel, said second vessel being constructed at. least in part ofa steam-permeable material, at least that part of said second vessel being spaced at least about 2 inches from the inner surface of said first vessel, said steam-permeable material being a textile fabric capable of converting superheated steam into sub,-

stantially saturated steam as the superheated steam permeates said permeable material, and means for supporting said textile article within said second vessel'at least about 1 inch from the inner surface of said steam-permeable material.

5. The apparatus of claim 4 wherein said steam-permeable material is a textile fabric having a basis weight of at least about1.5 ounces per square yard and a weave construction of at least about 35 picks per inch andabout 35 ends per inch.

6. The apparatus of claim 4 wherein said steam-per meable material is'a textile fabric having a basis weight of between about 1.5 ounces per square yard and about 4.9 ounces per square yard and a Weave construction of between about 35 and about 125 picks per inch and between about 35 and about ends per inch.

7. In an apparatus for stean1-treating a textile article including a first vessel capable of confining steam at superatmospheric pressures, and means for introducing steam under a pressure of greater than about 135 lbs./ in. into said first vessel, the improvement which comprises a second vessel within said first vessel, said second vessel being constructed at least in part of a steam-permeable material, at least that part of said second vessel being spaced at least about 4 inches from the inner surface of said first vessel, said steam-permeable material being a textile fabric capable of converting superheated steam into substantially saturated steam as the superheated steam permeates said steam-permeable material, and means for supporting said textile article within said second vessel at least about 3 inches from the inner surface of said steam-permeable material.

8. The apparatus of claim 7 wherein said steam-permeable material is a textile fabric having a basis weight of at least about 1.5 ounces per square yard and a weave construction of at least about 35 picks per inch and about 35 ends per inch.

9. The apparatus of claim 7 wherein said steam-permeable material is a textile fabric having a basis weight of between about 1.5 ounces per square yard and about 4.9 ounces per square yard and a weave construction of between about 35 and about 125 picks per inch and between about 35 and about 100 ends per inch.

10. In an apparatus for steam-treating nylon stockings knit from two-component nylon filaments including a first vessel capable of confining steam at superatmospheric pressures, and means for introducing steam under a pressure of up to about 135 lbs/in. into said first vessel, the improvement which comprises a second vessel within said first vessel, said second vessel being constructed at least in part of a steam-permeable material, at least that part of said second vessel being spaced at least about 2 inches from the inner surface of said first vessel, said steam-permeable material being a textile fabric having a basis weight of between about 1.5 ounces per square yard and about 4.9 ounces per square yard and a Weave construction of between about 35 and about 125 picks per inch and between about 35 and about 100 ends per inch, and means for supporting said stockings within said second vessel at least about 1 inch from the inner surface of said steam-permeable material.

11. In an apparatus for steam-treating nylon stockings, knit from two-component nylon filaments including a first vessel capable of confining steam at superatmospheric pressures, and means for introducing steam under a pressure of greater than about 135 lbs./in. into said first vessel, the improvement which comprises a second vessel within said first vessel, said second vessel being constructed at least in part of a stearn-permeable material, at least that part of said second vessel being spaced at least about 4 inches from the inner surface of said first vessel, said steam-permeable material being a textile fabric having a basis Weight of between about 1.5 ounces per square yard and about 4.9 ounces per square yard and a Weave construction of between about 35 and about 125 picks per inch and between about 35 and about ends per inch, and means for supporting said textile article within said second vessel at least about 3 inches from the inner surface of said steam-permeable material.

12. In a process for steam-treating a textile article prior to dyeing including the step of contacting said textile article with steam, the improvement comprising,

(a) enclosing said textile article within a second steam confining zone defined by a substantially permeable zone within a first steam confining zone, said substantially permeable zone characterized by conditions necessary to cause substantial conversion of any superheated steam into substantially saturated steam prior to contact with said textile article,

(b) introducing steam into said first steam confining zone, and

(c) permeating said steam into said second steam confining zone to allow contact of said textile articles with substantially saturated steam.

13. The process of claim 12 wherein said permeating is under such permeation conditions so as to comprise the steps,

(a) temporarily absorbing heat from any superheated steam to convert said superheated steam to substantially saturated steam and,

(b) difiusing steam into said second steam confining zone While resisting the passage of eddy currents,

and said substantially permeable zone is in spaced relation from both the said textile article and the boundary defining said first steam confining zone.

References Cited UNITED STATES PATENTS 1,717,110 6/1929 Markatos 223-51 2,341,729 2/1944 Lundgren-Johnson 68214 3,065,621 11/1962 Sam 68-214 3,132,846 5/1964 Siddall 2632 PATRICK D. LAWSON, Primary Examiner. JORDAN FRANKLIN, Examiner.

GEORGE V. LARKIN, Assistant Examiner. 

1. IN AN APPARATUS FOR STEAM-TREATING A TEXTILE ARTICLE INCLUDING A FIRST VESSEL CAPABLE OF CONFINING STEAM AT SUPERATMOSPHERIC PRESSURES, AND MEANS FOR INTRODUCING STEAM INTO SAID FIRST VESSEL, THE IMPROVEMENT WHICH COMPRISES A SECOND VESSEL WITHIN SAID FIRST VESSEL, SAID SECOND VESSEL BEING CONSTRUCTED AT LEAST IN PART OF A STEAM-PERMEABLE MATERIAL, AT LEAST THAT PART OF SAID SECOND VESSEL BEING SPACED FROM THE INNER SURFACE OF SAID FIRST VESSEL, SAID STEAM-PERMEABLE MATERIAL BEING A TEXTILE FABRIC CAPABLE OF CONVERTING SUPERHEATED STEAM INTO SUBSTANTIALLY SATURATED STEAM AS THE SUPERHEATED STEAM PERMEATES SAID STEAM-PERMEABLE MATERIAL, AND MEANS FOR SUPPORTING SAID TEXTILE ARTICLE WITHIN SAID SECOND VESSEL IN SPACED RELATION TO SAID STEAM-PERMEABLE MATERIAL. 